1. Field of the Invention
The present invention relates to an optical device for monitoring an optical intensity of an optical signal transmitted through an optical fiber and the like.
2. Related Background Art
Known as an optical device monitoring an optical signal transmitted through an optical fiber is one disclosed in Japanese Patent Application Laid-Open No. HEI 2-15203, for example. The optical fiber type optical demultiplexer disclosed in the above-mentioned publication comprises a substrate whose upper face has an optical fiber secured thereto. The substrate is formed with a groove which is at right angles to the fiber axis of the optical fiber and at an angle of 45° with respect to a side face of the substrate. A wavelength filter is inserted into the groove and bonded thereto. On the substrate, a photodetector is disposed so as to oppose the reflecting surface of the wavelength filter.